Many cardiological X-ray examinations require exposure of the heart of a patient from different spherical angles toward his support table. Stands supporting an X-ray source and an X-ray receptor on a radiation axis capable of being angulated about the patient table are well known as shown in U.S. Pat. No. 3,892,967. In some procedures two sets of X-ray source and receptor are used to allow biplane exposures of the patient from two angles without moving either radiation set, as shown in U.S. Pat. No. 4,426,725. Both single plane and biplane X-ray stands must be accommodated within the finite dimensions between the ceiling, floor and side walls of the hospital examination room, and at the same time must be capable of rotation through substantial solid angles from wide spherical angles toward the table.
One prior system, known as BICOR, manufactured by Siemens-Elema, Solna, Sweden suspends an X-ray set of source and receptor from a ceiling fixture supporting a bearing with a vertical axis of rotation for a curved track. Through the track slides a C-shaped, arcuate support with an X-ray source and receptor at opposite ends of the C. The problem with this system is that as the arcuate support swings the radiation axis toward a vertical plane, angulation of the radiation axis about the nearly parallel vertical axis of the bearing produces negligible angulation with respect to the patient, and does not provide the desired exposure of significantly different planes in the patient. One answer to the problem is provided by the Lateral ARC X-ray stand of Philips Medical Systems, Inc., Shelton, Connecticut, but at the expense of mounting two C-arms concentrically, one within the other, thereby increasing the floor to ceiling extent of the stand unacceptably beyond the finite dimensions normally available in hospitals, and seriously reducing the source-to-image-distance (SID) available between the X-ray source and receptor on the inner C-arm.
Accordingly it is the object of the present invention to provide an X-ray stand with which the radiation axis can be inclined close to vertical and yet be rotated at that inclination to substantially different angles in a plane through the patient, which also maximizes the length of the radiation axis between source and receptor with respect to the available dimensions of the hospital room, which maximizes the diameter of the single C-arm and the SID through the patient, and which allows greater freedom of movement of the C-arm around the patient table and free access of medical personnel to the patient.